Americans seem to carry bottled water everywhere they go these days. In fact, it has become the second most popular drink (behind soft drinks). But water lovers got a jolt recently when we heard that a new report had found that the benefits of drinking water may have been oversold. Apparently, the old suggestion to drink eight glasses a day was nothing more than a guideline, not based on scientific evidence.

But don't put your water bottle or glass down just yet. While we may not need eight glasses, there are plenty of reasons to drink water. In fact, drinking water (either plain or in the form of other fluids or foods) is essential to your health.

"Think of water as a nutrient your body needs that is present in liquids, plain water, and foods. All of these are essential daily to replace the large amounts of water lost each day," says Joan Kolemay, RD, dietitian for the Beverage Institute, an industry group.

Kaiser Permanente nephrologist Steven Guest, MD, agrees: "Fluid losses occur continuously, from skin evaporation, breathing, urine, and stool, and these losses must be replaced daily for good health," he says

When your water intake does not equal your output, you can become dehydrated. Fluid losses are accentuated in warmer climates, during strenuous exercise, in high altitudes, and in older adults, whose sense of thirst may not be as sharp.